When the bank collapsed -- or "readjusted" itself, as the Metropolitan Water Reclamation District would say -- along the North Branch by my house, neighbors anxiously pestered the alderman and the district for action.

In the past, the consequences of disparities between risk and premium were greatest in certain plans, especially the Blue Cross High Option, so naturally the older and sicker flocked there, until premiums were readjusted the following year, and they could move to another plan, joining a healthier cohort.